I googled the logmessages and topics about this cable but I couldn’t find any solution. I installed the new software image 5700-cmw710-system-r2432p01 (previous version 5700-cmw710-system-r2422p01) and made a reboot but the console shows again the “not supported” message. So I went to the interface and looked to the commands and I found something:

[HPE-FortyGigE1/0/54]using tengige
The interface FortyGigE1/0/54 will be deleted. Continue? [Y/N]:y
Reboot the member device to make the configuration take effect.
[HPE-FortyGigE1/0/54]save force
Validating file. Please wait…
Saved the current configuration to mainboard device successfully.
[HPE-FortyGigE1/0/54]quit
[HPE]quit
<HPE>reboot

after the reboot, the splitter cable was recognized and the transceiver error message doesn’t appear again. The “dis int brief” command shows also the four new interfaces:

After this I find an article at H3C to this command. It says “By default, a 40-GE interface is not split and operates as a single interface. The 10-GE breakout interfaces support the same configuration and attributes as common 10-GE interfaces, except that they are numbered differently. A 40-GE interface split into four 10-GE breakout interfaces must use a dedicated 1-to-4 cable.”

The interfaces are numbered from 1 to 4 but the cable has stickers from A to D:

I hope that I can help alot of people with this. From now on, Google will guide you to this article 😉 and when you don’t need this cable anymore, you can use it as a necklace: